In order to study the effect of aluminum ion implantation on the aqueous corrosion behavior of ZIRLO alloy, specimens were implanted with aluminum ions with fluence ranging from 1 × 10 16 to 1 × 10 17 ions/cm 2, using a metal vapor vacuum arc source (MEVVA) at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), respectively. Transmission electron microscopy (TEM) was used to examine the microstructure of the aluminum-implanted samples. Glancing angle X-ray diffraction (GAXRD) was employed to examine the phase transformation due to the aluminum ion implantation. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted ZIRLO alloy in a 1 M H 2SO 4 solution. It was found that the corrosion resistance of aluminum-implanted samples is worse than that of the as-received ZIRLO alloy. Finally, the mechanism of the corrosion behavior of aluminum-implanted ZIRLO alloy was discussed.